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Full text of "Metallurgy Of Cast Iron"

CHAPTER XLIII.
CHEMICAL FORMULA   FOR   MIXING AND MELTING vSCRAP IRON.
Scrap iron, as a general thing, is a product which has been re-melted one or more times, and hence must fairly show its true grade in a clean fracture. The advent of chemistry in founding will naturally cause some to ask: is it not necessary to know the metalloids in scrap iron as well as in pig metal in order to obtain desired results from mixtures? It is, of course, well to have analyses of scrap the same as with pig metal, whenever this is practical, but owing to the fact that scrap generally comes to the founder in a promiscuous manner, often a little of everything, working by analysis becomes largely impractical, either as to obtaining actual analyses or attempting to guess the chemical properties. In reality, it is not practical to define any of the metalloids in scrap iron by guesswork. About the only practical plan which the author can suggest is to consider and class scrap in the order of "grades," by numbers: as, for example, build an im-aginarybase to define " grades'" from the texture and grain which would be obtained by the remelting of pig metal, say, containing i.oo, 2.00, and 3.00 per cent, of silicon, respectively, with sulphur supposed to be constant at .030 and phosphorus and manganese as genffected by annealing are chiefly in lowering the total carbon in the skin and turning the combined that remains into temper carbon, the silicon, sulphur, manganese, and phosphorus remaining practically the same. The time occupied in annealing ranges from one to seven days, with castings packed in boxes, etc. This wide difference is due to different customs and the character of castings to be treated. The ovens used are of simple construction in small ladles to the moulds, than that coming from furnacesthat would stand the tests of the United States Government for gun carriage work rightfully belongs to Messrs. Robert Poole & Son Co. of Baltimore, Md., and Muirkirk pig iron made by me. This was in 1893. The War Department at first refused to accept cupola iron as gun iron, but when it was fully demonstrateduois Iron Co., Illinois Steel Co., Jefferson Iron Co., Kittan-ning Iron & Steel Co., C. A. Kelly Plow Co., Lebanon Furnace, Longdale Iron Co., Lackawanna Iron & Steel Co., Logan Iron........................   16,720     "                                     t-